Entangled photon sources have applications in many fields such as quantum communication, quantum computing and high resolution imaging. Entangled photons can be produced using parametric down conversion with optical non-linear crystals. However, there is a commercial need to be able to produce such a photon source using standard semiconductor materials due to its ease of integration with other components.
Recently, there has been work performed on attempting to generate entangled photon states using bi-exciton decay in quantum dots.
In order to produce entanglement it is necessary to produce a stable neutral bi-exciton which decays to a stable neutral exciton.